The inventions described herein relate in general to digital receivers for radio frequency (RF) communications. More specifically, the inventions relate to arrangements having a digital correlator operating at RF frequencies that can be used as a basic building block of a multi-function digital receiver that utilizes superconductor technology.
FIG. 1 (Prior Art) is a block diagram of a conventional receiver. Typically, an RF signal from an antenna 100 is coupled to a low noise front end 102 which may provide amplification and/or filtering to isolate a band of frequencies of interest. An output signal from front end 102 is mixed with a local oscillator signal from a local oscillator 106 to move the received RF signal down to an intermediate frequency (IF) that is considerably lower than the RF signal initially received. The IF signal may be filtered by a filter 108. The IF signal is then coupled to a digital post processor 110 to recover the information of interest. The digital post processor 110 may be a demodulator, a deinterleaver, a decoder, a despreader, a dehopper, etc., depending upon the type of signal originally transmitted and to be recovered. For example, in a CDMA cellular telephone receiver the signal of interest may be a so-called ‘chip signal’